Question posted in 
Auto contraints seems like a bit of a chore. I have a bunch of elements in my main view (this is a single-view app) inside Main.storyboard. So imagine a few labels, buttons, controls, etc.
For example, take one label that says “Hello World” that’s centered horizontally in the upper portion of the screen.
I need to add the following constraints to make it appear “normal” in my various devices ipad/iphone:
- Horizontal Center constraint
- Leading Space
- Top Space
- Trailing Space
It works, but it seems like a lot of work, I don’t remember doing this work in the good old days (~3 years ago) with struts and springs. So I need to add all these constraints to each of my other elements too. So if I have 10 elements, I need roughly 10×4=40 contraints? Is this the ideal way to do this?
If it were up to me a view and the elements as I place them in the view and all controls in it would just be stretched relatively to fit the size of the device. An example would be like in photoshop, where we just decide what the overall image looks like and then scale the image to just fit the dimensions that we want. Is this possible in xcode?
Note that my app is just portait only – for iphone/ipad, but looks exactly the same in both (ie same layout for the controls)
2
Answers
You don’t need to set that many constraints.
Horizontal center + top space would be enough given your example, or leading, trailing and top space.
If you are setting leading, trailing and horizontal center, you are over-specifying in that axis and possibly giving the auto-layout system contradictory information that will cause problems.
For that specific example: no, you only need a horizontal center and a top space, because UILabels have an intrinsic content size so their width and height is specified by their content and not constraints (unless you want them to be).
You didn’t do this work in the good old days because Auto Layout wasn’t on iOS then and there was only one particular possible iPhone size at the time: now there are 4. Auto Layout is an essential tool for modern iOS development.
As for controls stretching relatively to the device size, it depends on the control, but in general standard controls maintain the 44 point touch target rule – for example nav bars have gotten wider to accommodate wider phones but they haven’t gotten any taller, because the larger screen size should be used to display more content instead of more chrome.
But yes, if you wanted to have controls have particular dimensions based on device size that is definitely possible with Auto Layout.